It looks like a f****d up stamp.  The river is blocked by a cliff at the water, and if you look in the ocean you can see the river continue on underneath the water.

There have been problems with rivers ever since E:WoM.  I posted a screen cap and saved game from .50 showing a river running into and 1 tile past the shore, with a waterfall 2 tiles out into the ocean.

Parrotmath, despite his great talents, hasn't been able to fix all of these problems.

And that was the problem with them.

That is a problem with a particular stamp... I haven't delved into fixing stamps... I'm still unable to control the floating particle effects, no matter what I try.

wasn't there a cloud of death in WoM at some point?